The invention relates to a device for covering depositories.
Covering depositories serves several purposes. The important ones are:
Providing a site for plants and animals in accordance with reforestation measures.
Preventing surface leakage water from penetrating into the depository body.
Preventing uncontrolled emissions from the depository body into the cover soil and into the atmosphere.
These tasks are essentially fulfilled by a basic layer structure of the depository cover comprising, from the top down: (a) humus, (b) root soil, (c) a substructure for draining surface leakage water, (d) a barrier layers, (e) degasification drainage structure, and, (f) an equalization layer.
The humus and the root soil are the base for a plant cover over the depositories, while the upper drainage structure serves for preventing backwater accummulations over the barrier layer which accumulations would interfere with the growth of plants. The barrier layer performs two functions: to prevent access of water into the depository body and to prevent the escape of gases from the depository body. Gases retained by the barrier layer are removed in a large-area gas drainage structure. The gas drainage is placed on an equalization layer disposed over the storage masses proper.
In known proposals for the layer structure, the substructure for draining surface leakage water consists of a gravel filter bed up to 50 cm thick with drainage pipes, the barrier layer is made of clay with thicknesses between 0.30 and 0.80 m and the gas drainage structure comprises a coarsegrain filter gravel layer with thicknesses of up to 0.50 cm and built-in gas collecting pipes. In such proposed depository covers the drainage and barrier layers reach a total thickness of between 1.00 to approximately 1.50 m. The costs for shipping and installation are correspondingly high. Each layer must be brought in individually with, in part, heavy equipment and must be densified.
Objects of the invention are to reduce the total thickness of the drainage and barrier layers in the above-described type of depository cover, to reduce the manufacturing and installation costs and to keep the required cost for installation equipment as well as the installation times as low as possible.